1. Field of the Invention
This invention relates generally to passenger oxygen modules equipped with chemical oxygen generators, and more particularly concerns an oxygen generator mounting structure that permits the oxygen generator to be deployed to a safe position to improve heat dissipation from the chemical oxygen generator away from the chemical oxygen generator container and Structures surrounding the oxygen container.
2. Description of Related Art
Chemical oxygen generators are used in passenger aircraft as a source of oxygen for use by the cabin occupants to protect them from hypoxia in the event of a decompression or depressurization of the passenger cabin. However, the chemical reactions that release oxygen in such chemical oxygen generators are typically highly exothermic, producing a significant amount of heat when the generator is actuated during an emergency. Such heat can damage adjacent airplane structures, especially when those structures are made from lightweight aerospace composite materials.
While such structures can be protected from the heat produced by a chemical oxygen generator by installation of thermal insulation, doing so increases the weight of the installed equipment, which is undesirable for use on airplanes. While insulation can also be achieved by installation of the chemical oxygen generator with a greater air space from the walls of the oxygen module, this approach unfortunately results in oxygen modules that occupy more space, decreasing useful cabin space. Chemical oxygen generating modules are commonly installed beneath the overhead luggage bins, so that if space is added to oxygen modules to facilitate heat management, the oxygen modules are thicker, and the clearance between the heads of the cabin occupants and the module is reduced, which is also undesirable for airlines.
With reference to the prior art illustrated in FIGS. 1A and 1B, one presently known conventional oxygen generator mounting system mounts an oxygen generator 10 on a pivoting arm 12 in an oxygen generator container 14, and pivots the oxygen generator to a lowered position 16 to improve heat dissipation when the oxygen generator container lid is opened to deploy an oxygen mask. As is shown in FIG. 1A, when the pivoting type of oxygen generator is deployed at some angle xcex8, at any angle xcex8 between 0xc2x0 and 90xc2x0, the horizontal coordinate x of the generator is given by the expression: r cos (xcex8), and the vertical coordinate y is given by the expression: r sin (xcex8). However, for a pivoting movement of any given angle xcex8, the extent of displacement of the oxygen generator is limited by the length of the pivot arm, which is in turn limited by the dimensions of the oxygen module. Thus, while such a system enjoys the benefits of simplicity associated with a pivoting system, such a system imposes restraints on the packaging and deployment enveloper of emergency oxygen systems. It would be desirable to provide an emergency chemical oxygen generating system for passenger aircraft with a mounting mechanism that would allow the oxygen generator to reach a position that lies outside this limited envelope of positions that can be reached by use of a pivoting mounting system for the oxygen generator. The present invention meets these needs.
Briefly, and in general terms, the present invention provides for an emergency chemical oxygen generating system for passenger aircraft in which the oxygen generator is mounted on a structure that permits the oxygen generator to be displaced vertically and horizontally away from the walls of the container for the oxygen generator when the door of the module is opened, in order to reduce the heating of the container walls, the air gap surrounding the container walls, and the surrounding structures behind the oxygen container. By causing the generator to translate downward and sideways, the choice of positions in which the generator comes to rest can be selected over a wider range of possibilities than if a pivoting repositioning mechanism is employed.
The use of a sliding mounting mechanism allows the generator to reach a position outside the envelope of positions that can be reached by use of a pivoting mounting mechanism. The horizontal and vertical displacements are defined by the angle at which the sliding mounting mechanism is installed, and by the extent of the sliding displacement accomplished by the sliding mounting mechanism.
The invention accordingly provides for an emergency oxygen supply system utilizing a sliding mechanism for mounting of a chemical oxygen generator. The sliding mechanism advantageously slides and may also pivot, for moving the chemical oxygen generator away from the walls of an oxygen module during operation of the generator. Such a capability enhances the ability to avoid heat damage to the oxygen module from the generator and improves the space utilization of the module within the passenger compartment.
In one presently preferred embodiment, the sliding mechanism comprises a telescoping assembly having one end secured to the container and the other end secured to the generator, and having multiple sliding segments producing a total sliding displacement (L) that results in a greater horizontal or vertical displacement than can be accommodated by a pivoting means having dimensions to fit into the confines of the oxygen module.
In an alternate embodiment, the sliding mechanism comprises a slot in the side of the module wall, with a tab attached to the generator, such that the tab slides within the slot, allowing for downward sliding of the generator.
In another alternate embodiment, the sliding mechanism can comprise an arrangement of channels and rollers analogous to those used to permit a file drawer to be moved from a stored position to a position in which the drawer""s contents can readily be accessed.
In another aspect of the invention, the movement of the generator from a stowed position to a use position can also initiate the flow of oxygen. For example, the actuation pin of the oxygen generator can be attached to one end of a short lanyard, while the other end of the lanyard can be attached to the module structure, so that when the oxygen generator slides downwardly in relation to the oxygen module structure, the lanyard will withdraw the actuation pin, initiating oxygen flow.
These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.